The issue now is that you need to buy cash one-way returns. These will often be more expensive than a full round-trip with cash (no, it doesn't make intuitive sense). Therefore, instead of $1500pp roundtrips, you'll have to spend $2500pp just to get back, and have spent all your miles to get there. If this is the situation you're in, you can cancel what you've booked for free within 24 hours of booking (however, note that award inventory you've booked may not reappear for later booking).

The revenue tickets matching the return award availability you find are surely purchasable, though you may need to use multi-city search to force a particular routing, and particularly if you are moving among multiple carriers, the price might not look at all competitive.

Is your husband's ticket being covered by work, or paid by you? His elaborate trip with multiple stopovers and a need for only a single seat on most legs is much more conducive to the strengths and limitations of award bookings. In your shoes, I would probably buy your ticket and the child ticket (since you want particular desirable flights on particular days) and book your husband with miles.